Many new handheld devices have become available, including laptops, smartphones, PDAs, etc. Different methods have previously been used to communicate between a handheld (portable) device and other devices. For example, Bluetooth technology has previously been used. However, methods of secure device association such as those used in Bluetooth are subject to spoofing. Therefore, a need has arisen for communication between devices so that devices can securely and uniquely identify one another, for example, to share resources in a manner that is secure but does not add increased complexity, cost, space, and/or power, etc.